Radiation Treatment Timing and Dose Delivery: Effects on Bladder Cancer Cells in 3D in Vitro Culture
Larry Bodgi,
Joelle Al-Choboq,
Tarek Araji,
Jolie Bou-Gharios,
Joyce Azzi,
Rafka Challita,
Charbel Feghaly,
Hisham F. Bahmad,
Toufic Eid,
Fady Geara,
Youssef H. Zeidan,
Wassim Abou-Kheir
Affiliations
Larry Bodgi
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Joelle Al-Choboq
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Tarek Araji
Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Riad El-Solh, Beirut 1107 2020, Lebanon
Jolie Bou-Gharios
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Joyce Azzi
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Rafka Challita
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Charbel Feghaly
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Hisham F. Bahmad
Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Riad El-Solh, Beirut 1107 2020, Lebanon
Toufic Eid
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Fady Geara
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Youssef H. Zeidan
Department of Radiation Oncology, American University of Beirut Medical Center, Riad El Solh, Beirut 1107 2020, Lebanon
Wassim Abou-Kheir
Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Riad El-Solh, Beirut 1107 2020, Lebanon
While radical cystectomy remains the primary treatment of choice for bladder cancer, increased evidence supports the use of bladder-preservation strategies based on adjuvant radiotherapy. This highlights the need for a better understanding of bladder cancer radiosensitivity to different types of treatment deliveries. The purpose of this study is to analyze the effect of treatment time, dose and fractionation on the number and sizes of grown three-dimensional (3D) bladder cancer spheres, and to assess the capacity of the linear-quadratic model in describing the response of cells cultured in 3D. 3D MatrigelTM-based cultures were employed to enrich for cancer stem cells (CSCs) from three human bladder cancer cell lines, RT4, T24 and UM-UC-3. Three single dose radiation treatments were performed at different time points after plating, and sphere number and sizes were assessed. Anti-CD44 immunofluorescence, clonogenic assay and anti-γH2AX staining were also performed to analyze the cell lines’ radiosensitivity. The radiosensitivity of spheres was dependent on the treatment timing after plating. Current linear quadratic dose fractionation models were shown to over-estimate radiosensitivity in 3D models. Our results showed the importance of treatment timing on the radio-response of bladder cancer spheres. We also demonstrated that bladder cancer spheres are more resistant to dose-fractionation than the estimation from the theoretical linear-quadratic model.
